Target practice ammunition



P 1967 H.STADLER ETAL TARGET PRACTICE AMMUNITION Original Filed April19, 1965 4 FIG. 2

FIG. I

FIG. 2b

.FIG. 20

FIG. I0

INVENTORS. HANS STADLER THOMAS SCHINNERER HANS UMBACH United StatesPatent 3,342,134 TARGET PRACTICE AMMUNITION Hans Stadler, Numberg,Thomas Schinnerer, Furth, Ba-

varia, and Hans Umbach, Stadeln, Germany, assignors to Dynarnit NobelAktiengesellschaft, Troisdorf, Germany Continuation of application Ser.No. 449,003, Apr. 19, 1965. This application Sept. 20, 1966, Ser. No.580,832 Claims priority, application Germany, Apr. 30, 1964, D 44,311 8Claims. (Cl. 102-41) ABSTRACT OF THE DISCLOSURE A practice cartridgehaving a cartridge case and a projectile made in one piece and ofthermoplastic material, and having an intentional breaking point betweenthe projectile and the case. The breaking point consists of a radialconnection between the rear portion of the projectile and the forwardportion of the case, so that the cartridge case is stressed in shear bythe propellant gases.

This application is a continuation of application Serial No. 449,003,filed April 19, 1965, now abandoned.

The present disclosure relates to practice ammunition, and moreparticularly to such practice ammunition in which the cartridge case andthe shell are made in one piece of thermoplastic material and in which awell-defined and predetermined place of separation is provided betweenthe case and the projectile. The projectile and case being connectedsolely by a substantially cylindrical breaking zone that will rupturesubstantially exclusively in shear.

Known in the prior :art is a target practice ammounition in which thecartridge case and the shell are made in one piece of thermoplasticmaterial and in which an intended breaking or separating place isprovided between the shell and the cartridge case. Apart from arelatively low overall weight, one obtains by the use of thermoplasticmaterial with this known type of cartridge also a small weight of theshell part and therewith the desired small maximum flight distance.Therebeyond a safe eparation of the shell from the cartridge case isassured by the arrangement of the intended breaking place. Thus, therequirements made of this type of cartridge are fulfilled verysatisfactorily by this prior art target practice cartridge 1 especiallyas it exhibits additionally the advantage of simple manufacture and lowcost.

However, as has been found, it may happen with this type of prior arttarget practice cartridge that during the firing the separation betweenthe shell and case at the intended breaking place takes place in such amanner that at some places of the end of the shell, parts projectingoutwardly beyond the same of the mouth portion of the case remain stuckthereon. The cause of this sometimes not altogether clean separationbetween shell and case is r to be seen essentially in the arrangementand construction of the intended breaking place which have as aconsequence that the plastic material at the connecting place betweenshell and case, that is, within the area of the intended breaking place,is stressed exclusively in tension during the separating operation.Since the firing image is falsified by parts adhering at the shell andinfluencing its flight and its weight, a completely satisfactory andsmooth separation between shell and case at the intended breaking placeis the more important the greater the required firing precision.

It is the aim of the present invention to eliminate the aforementioneddisadvantage, that is, to create a target practice cartridge in whichthe separation between shell and case takes place with certainty in sucha manner that after the separation, no parts of the case adhere anylonger at the shell which influence the weight and the flight path ofthe shell in an undesirable manner, that is, which might render the samefalse. For a target practice cartridge in which the cartridge case andthe shell are made in one piece of thermoplastic material and in which adefined intended breaking place is provided between the case and theshell, it is therefore proposed in accordance with the present inventionto so construct and arrange the intended breaking place as radialconnection between the rear end section of the shell part and theforward end section of the case part receiving the same that is stressedby the pressure of the propellant gases acting on the shell partexclusively in shear.

Customarily, the cartridge cases pass over by means of a part, theso-called case shoulder, tapering conically toward the forward end ofthe cartridge case, from a rearward wider part into a forward narrowerpart, the socalled neck of the cartridge case, whose forward end isreferred to as case mouth. It has now been discovered that theconstruction in accordance with the present invention of the intendedbreaking place as radial transition between the end of the shell partand the case part may be realized in a particularly simple andappropriate manner if the shell part is extended about the usualcartridge case neck section and the also usual cartridge case shouldersection and the intentional breaking place is constructed as transitionbetween the thus constructed shell part and the end of the powder spaceof the cartridge case.

In addition to the intended smooth and clean separation between theshell part and the case with which the usually present diametricdifferences of the cartridge are utilized advantageously, it is possibleto achieve in connection therewith also an arrow-like shell, that is, ashell in which the center of gravity is disposed to a greater or lesserextent in front of the shell center if, according to a further proposalof the present invention, the extension is provided with a central axialaperture or recess starting from its rear end and extending over a moreor less large part of the shell extension and possibly also of theshell, properly speaking. Not only the location of the center ofgravity' of the 'shell but also its weight may be influenced by such acentral aperture or recess whereby it is quite possible by acorresponding dimensioning of the aperture as regards its length and itscross section by reason of the larger shell weight conditioned by theshell extension to obtain a suitable and sufliciently heavy shell partfor use also in automatic weapons.

Furthermore, an elastic yieldingness of the shell extension section isachieved by the arrangement and construction of such a central apertureor recess whereby the shell extension section is pressed under thepressure of the propellant gases penetrating into the aperture or recessaround the entire circumference thereof securely into the barrel of thegun so that during passage of the shell part through the barrel, aparticularly good seal with respect to the propellant gases is achieved.This seal can be further improved in that the shell extension section isconstructed with an outer diameter increasing in the rearward direction,for example, of slight conical configuration which additionally alsofavors the achievement of an advantageous transition of shell tocartridge case shoulder.

Accordingly, it is an object of the present invention to provide atarget practice ammunition of the type described above in which theshell part and cartridge case are made in one piece of plasticmaterialand which eliminates by extremely simple and operationallyreliable means the aforementioned drawbacks and shortcomings encounteredwith the prior art constructions.

Another object of the present invention resides in the provision of atarget practice cartridge of the type in which the shell andcartridg ecase are made in one piece which assures a clean, smooth and completelysatis- 1 factory separation ofv the shell from the cartridge; case underall operating conditions. i

A further'o-bject of the present invention resides :i-n-- the provisionof atarget practice cartridge in which the shell is made in one piecewith the cartridge case of the thermoplastic material and which isprovided? with an intentional breaking place between the shell and .thccartridge case ofsuch arrangement and constructionthat acompletcly cleanseparation occurs at the breaking place devoid of any parts adhering tothe rear end of the shell that might impair or influence its flightcharacteristics. Still another object of the present invention re 2 Isides in the provision of a target practice cartridge. of

than attainable heretofore. I

'-unitary therrnoplastic construction as'rcgards shell and v v cartridgecase which assures a greater firing accuracy scribed above whichachieves all of the aforementioned provision of a unitary targetpractice cartridge consisting of thermoplastic :shell and cartridge casein which the i shell maybe made of relatively large: weight :notwithstanding theuseofthermoplastic rnaterialso as to facili- I 'tate and irnpr'ove it's use with automatic weapons.

. I A. still. further object of the present: invention; resides 1 in theprovision of a target practice ammunition of; "thermoplastic'niaterialthat not. only achieves a com ,pletely. satisfactory and meanseparation of the cartridge 7 y 1 case from the vintegrally formedshell, but which also E bears a particularly good seal of the shellduringv passage thereof through the barrel with respect to thepropellant 1 ases." These and other objects,

features and advantages. of the present invention will become moreobvious from the following description when taken in connection with theaccompanying drawings which shows, for purposes of illustration only,several embodiments in accordance with the present invention andwherein:

FIGURE 1 is a partial axial cross-sectional view through a targetpractice cartridge in accordance with the present invention in which theintentional breaking place is arranged between the shell and the forwardend of the cartridge case neck section,

FIGURE 1a is a partial cross-sectional View, on an enlarged scale, ofthe target practice cartridge of FIG- URE 1, illustrating a slightlymodified construction,

FIGURE 2 is a partial axial cross-sectional view through a modifiedembodiment of a target practice cartridge in accordance with the presentinvention in which the intentional breaking place is displacedrearwardly by the length of the cartridge case neck section and shouldersection to the place of transition from the normally present cartridgecase shoulder into the wider rear section of the cartridge case,

FIGURE 2a is a partial cross-sectional view, on an enlarged scale, of amodified construction of the conmeeting place between the shell and thecase, with the target practice cartridge according to FIGURE 2, and

FIGURE 2b is a partial cross-sectional view, on an enlarged scale,similar to FIGURE 2a of a still further modified embodiment of theconnecting place between the shell and cartridge case with the targetpractice cartridge of FIGURE 2.

Referring now to the drawing, wherein like reference numerals are usedin the various areas to designate like parts, the target practicecartridge according to FIGURE 1 is provided as usual with a cartridgecase 1 having a large cylindrical rear portion 2, a forwardly conicallyaims and objects by extremely simple :rneansyet permits at the same timeby extremely simple means i an :adjust.-=

:ment of the center of gravity of the. shell :in any desired mannerqv IA further object of the presentimventionresides inithe transition fromthe case :llor from the case shoulder 4 f to the shell 5, theradiallyextending, annularly shaped and'relatively narrow cut-i:n:or notch. 6Whose depth: 7 corresponds in thiscase:exactlytothewell thickness of 1 i,thecartridge case neck portion 4 so that in practice the. 1 1

shell 5 extends in effect withits extension 7 slightly into I the caseneck-portion4 andthus is connected :with thel j case 1 exclusiyely'intheradial direction by way of this extension 7. The' dash linesin FIGURE :1indicate that the shell 5 may be provided. in its core with an aperture.

. or: recess open toward the bottom, vi.e., the shell need,

not necessarily be solid throughout.

As may readily be seen from. the. drawing,'the condi- =tions'are sochosenthat. the material has its weakest cross section at thetransition: from; the shell. 5 to; the. vcase 1 so that definedintentional. breaking place. is

achievedpFurthermore, the. conditionsareialso so chosen'that'duringfiringof the cartridge, the material is stressed 'at' thisplace :by the pressure of .the powder gases. ex-

clusively in shear and, therewith av smooth and cleanseparation of the;shell :5 from the case. 1 isachicvcd. I I 7 In order to achieve. a still.rnore clearly defined ini tended breaking place: and therewith a stillmore smooth I. I

and more clean separation between the shell 5 and the case 1; theconstruction of; this place may also be realized I approximately asshown in the enlarged cross section: of FIGURE la, thatii s',withianannular groove ornotch- 12 extending: :overthe entire.circumference or in a .similar.manner.v 1 1 I I In the, embodiment {ofFIGURE? 2, the shellj .5, properly speaking, of solid. construction and.having an external surface slightly conically enlarged toward the i e'arwhich-jas indicated by the dash lines in FIGURE 2-may :be I providedalso in; this case within the core I v I thereof with a more or lesslarge aperture or recess'open I toward the bottom, is provided in therearward direction toward the rear end, which extension 8 corresponds tothe usual cartridge case neck portion 4 and the cartridge case shouldersection 3, normally provided with such cartridges and indicatedschematically in dash and dot lines. The rear end of the extension 8projects slightly into the forward end of the wide rear section 2 of thecartridge case 1 having a cylindrical external surface and slightlyconically tapering internal surfaces becoming wider in the directiontoward the forward end so that the shell 5 with the extension 8 thereofis connected with the cartridge case 1 corresponding to the integralmanufacture of the cartridge exclusively at this place and in the radialdirection.

The arrangement is thereby made in such a manner that the annularlyshaped area of slightest material crosssection coincides with theimaginary extension of the conical enlargement of the internal surfacesof the wide case section 2. It is achieved by this arrangement andconstruction that the area of smallest material cross-section defined asthe intended breaking place is stressed during firing of the cartridgeby the powder gases practically exclusively in shearing and a clean,smooth separation is achieved correspondingly between the shell 5, 8 andthe case 1.

Therebeyond it follows from this arrangement and construction that allplaces of the provided breaking cross section are disposed in acircularly shaped, conically tapered surface becoming smaller toward therear so that after realized separation of the shell and case, the rearouter edge of the extension 8 is chamfered so to speak of, that is, thebreaking surface is disposed practically in the aerodynamic shadow ofthe flying shell. Accordingly, in this case even with an eventuallysomewhat rough breaking surface, no parts thereof project beyond thelargest diameter of the shell 5 or the extension 8 thereof so that theflight path is not impaired.

The extension 8 is provided in the illustrated embodiment with a centralaperture or recess 9 extending over the entire length thereof andconically enlarged toward the rear whereby the conical incline or slopeis chosen slightly larger than that of the external surface so that thewall thickness of the extension 8 is slightly reduced toward the rear.The advantage of a particularly good elastic adaptation of the extension8 to the barrel of the gun during passage thereof through the same andcorrespondingly, a particularly good seal with respect to the propellantgases results therefrom. Of course, any other type of construction ofthe central aperture or recess may also be provided, for example, suchan aperture or recess that a uniform wall thickness results or alsoespecially such a construction that the aperture or recess extends inthe longitudinal direction only over a more or less large part of theextension. It follows therefrom that one can at will readily influencethe Weight and the center of gravity of the shell part in the desired oralso necessary manner.

As shown in FIGURES 2a and 2b, a still more clear definition of theintended breaking place, that is, a still more sudden cross-sectionalchange at this place may be achieved if the connection between theextension 8 and the case part 2 does not take place directly at themutually overlapping ends but slightly displaced toward the rear intothe case part 2 (FIGURE 2a) and possibly also slightly displaced in theforward direction from the end of the extension 8 (FIG. 2b), that is,this connection takes place in such a manner that the extension 8 andthe case part 2 are efiectively slightly further slipped one into theother and annularly shaped notches 10 or 10 and 11 result or areprovided.

While we have shown and described several embodimen in accordance withthe present invention, it is understood that the same is not limitedthereto but is susceptible of numerous changes and modifications asknown to a person skilled in the art. For example, the illustratedembodiments are not limited to a certain calibre of the target practicecartridge and accordingly the illustrated dimensions are therefore to beunderstood only as exemplary which, of course, is also true insofar asthe shape of the shell is concerned.

Thus, it is obvious that the present invention is not limited to thedetails described and illustrated herein but is susceptible of numerouschanges and modifications as known to any person skilled in the art andwe therefore do not wish to be limited to these details but intend tocover all such changes and modifications as are encompassed by the scopeof the appended claims.

We claim:

1. A cartridge having a firing axis of symmetry, comprising: a plasticbullet portion having a forward free end and a rearward substantiallycylindrical portion: a plastic tubular cartridge case for enclosingpropellant powder and having a forward substantially cylindrical tubularportion only partially encircling said bullet rearward cylindricalportion to define overlapping cylindrical portions; the inside diameterof said overlapping portion of said forward substantially cylindricaltubular case portion equalling the external diameter of said overlappingportion of said bullet rearward cylindrical portion; and saidoverlapping portions being homogeneously integrally connected alongtheir entire adjacent peripheries to form a one piece plastic bullet andcase structure to form the sole connection between said bullet portionand said cartridge case, and to constitute means for forming anintentional cylindrical breaking zone between said bullet portion andsaid cartridge case that is stressed substantially exclusively in shearby the pressure of the propellant gases during the firing of thecartridge.

2. The cartridge according to claim 1, wherein said cartridge caseincludes a rearward case portion, a forward neck portion and a shoulderportion connecting said neck portion and said rearward case portion.

3. The cartridge according to claim 1, wherein said bullet portion isprovided with a central axial recess opening in the rearward direction.

4. The cartridge according to claim 3, wherein the walls forming saidaxial recess decrease in thickness toward the rearward end in a uniformmanner.

5. The cartridge according to claim 1, wherein said cartridge case has auniformly increasing internal diameter toward its forward end.

6. The cartridge according to claim 1, including an annular wedge shapednotch in at least one of said cylindrical portions immediately adjacentsaid overlapping portions.

7. The cartridge according to claim 6, including an additionalwedge-shaped annular notch in the other of said cylindrical portionssubstantially identical to and opening in the opposite axial directionfrom said first-mentioned wedge-shaped annular notch.

8. The cartridge according to claim 1, wherein said cartridge isconstructed of a thermoplastic material.

References Cited FOREIGN PATENTS 4/1961 Austria. 4/ 1960 Great Britain.

1. A CARTRIDGE HAVING A FIRING AXIS OF SYMMETRY, COMPRISING: A PLASTICBULLET PORTION HAVING A FORWARD FREE END AND A REARWARD SUBSTANTIALLYCYLINDRICAL PORTION: A PLASTIC TUBULAR CARTRIDGE CASE FOR ENCLOSINGPROPELLANT POWER AND HAVING A FORWARD SUBSTANTIALLY CYLINDRICAL TUBULARPORTION ONLY PARTIALLY ENCIRCLING SAID BULLET REARWARD CYLINDRICALPORTION TO DEFINE OVERLAPPING CYLINDRICAL PORTIONS; THE INSIDE DIAMETEROF SAID OVERLAPPING PORTION OF SAID FORWARD SUBSTANTIALLY CYLINDRICALTUBULAR CASE PORTION EQUALLING THE EXTERNAL DIAMETER OF SAID OVERLAPPINGPORTION OF SAID BULLET REARWARD CYLINDRICAL PORTION; AND SAIDOVERLAPPING PORTIONS BEING HOMOGENEOUSLY INTEGRALLY CONNECTED ALONGTHEIR ENTIRE ADJACENT PERIPHERIES TO FORM A ONE PIECE PLASTIC BULLET ANDCASE STRUCTURE TO FORM THE SOLE CONNECTION BETWEEN SAID BULLET PORTIONAND SAID CARTRIDGE CASE, AND TO CONSTITUTE MEANS FOR FORMING ANINTENTIONAL CYLINDRICAL BREAKING ZONE BETWEEN SAID BULLET PORTION ANDSAID CARTRIDGE CASE THAT IS STRESSED SUBSTANTIALLY EXCLUSIVELY IN SHEARBY THE PRESSURE OF THE PROPELLANT GASES DURING THE FIRING OF THECARTRIDGE.